This article looks at the ethical and diversity implications of high billable hour requirements. While corporate counsel have increasingly demanded a diverse legal workforce and emphasized the need to lower the costs of outside counsel, law firms have not responded to these concerns in a manner that is producing results. Instead, women continue to drop out of law firm practice at higher rates than their male counterparts and the costs of legal services remain high. High billable hour requirements exacerbate both these problems and have implications as well for ethical lawyering. Using data from a variety of disciplines, the article shows that not only do high billable hour requirements make large law firms difficult places for women to succeed, but they also foster work environments that are inefficient and therefore cost clients more. This has implications on a lawyer’s ethical duty not to discriminate based on sex and not to charge an unreasonable fee, and also increases the potential of lawyers making mistakes. Studies of lawyers suggest that high billable hour requirements exacerbate the difficulties women have in practice, especially for those women who have family responsibilities. This leads to high dropout rates from law firm practice that hurt both law firms and their clients. Lowering billable hours will increase the possibility that women will succeed in these workplaces while making lawyers more efficient. Using studies of sleep deprivation and sleep restriction, this article explores what clients are getting for their money from sleep-deprived high billable hour lawyers. It is clear that both sleep deprivation and chronic sleep restriction impair the average person’s ability to function on many levels—including neurocognitive performance that has important implications for lawyering. In addition, studies of workplace productivity have shown that limiting working hours can actually increase productivity. Thus, limiting hours logically should produce more efficient and ethical lawyering while making law firms more feasible work environments for women.